Eremogone kingii var. glabrescens (King's sandwort). Sabulina nuttallii var. gracilis (Nuttall sandwort) is possible too., but the leaves (next image) and picture comparisons aim me toward the first. The characteristics separating Eremogone and Minuartia in the Jepson key -- ovary sutures and fruits -- are not in view here.
